Can I convert my whammy4 to run off of DC power?

[ppatchmods]

Can i convert my whammy to use DC current instead of AC like i would an old boss pedal? thanks

[jkokura]

With the prominence of 9V DC being the main power needs of most guitar pedals, you would think that Digitech would have made it that way if it could have been made with that power need. I wonder if there's a reason it needs the 18V AC?

Jacob

[ppatchmods]

it actually takes a 9vac 1.3 amp power supply. could i use a bridge rectifier? where would i put that on the circuit?

[ppatchmods]

i have a feeling that it is AC power because of the amps it draws. is this correct?

[jkokura]

I have no idea, but that is a massive amount of power. The only other pedal I know of drawing that much are the Eventide units which need a similar power setup. I'm not sure if they're ac or dc, but the current draw on them is supposed to be close to 1500 mA, or at least that's what their literature says.

What's the reason you're wanting to do this? Do you have a 9V 2A supply that you want to use? Is it about getting all the power needs without using a wallwart?

Voodoo labs has a new power supply, the ISO 5 or something like. I've been thinking about getting both the Whammy and an Eventide unit, and I think that ISO5 will power both (maybe not simultaneously).

*Edit* Just realized the Iso5 is DC only, no AC for the Whammy. Perhaps that's why it you'd want to do the mod *Edit*

Or are you modding just cause you like to experiment?

Jacob

[ppatchmods]

bought a whammy and no PS, but the 1spot is 1700ma 9vdc. thought i could you something like that

[space_ryerson]

A friend of mine had a Wh-4 with a dead ps that he gave me. I tried using my WH-2's ps (9v AC, 900mA I think), and the WH-4 just does this 'one led flash no work' thing. So, I tried a non-digitech 9v AC 1.3 amp ps, and have the same problem! I tested the voltage from the ps, and it was closer to 10v AC, so I called Digitech, and they sell the bloody ps for $40! I'm all ears for a solution that doesn't involve me paying $40 a ps that will just fail in a year or two.

On a tangent, the ps for the Alesis 3630 compressor works quite well with the WH-2. Better than the original digitech one!

[rustypinto]

Just plug the DC adapter in and see what happens. There usually isn't any harm in doing so, the only loss is a diode drop or two and ground not actually being at 0VDC because of any types of rectifiers. (NOTE: You can't do the opposite, Eg. plugging AC adapters into units without rectifiers!)

The CPU in that thing is such a power hog. I've heard of many different types of power hungry digital effects dragging down the voltage on some of those 1-spot type adapters used with a chain of effects, its happened to me plenty of times. You might as well just use a dedicated supply. Just don't void any warranties!

[jkokura]

The best supply out there could be the burkey Flatliner, so if you want good power for it, you could spend the 350 for a flatliner pro 

Anyway, I don't know how you use pedals (on a board, freebird, one at a time or lots and lots) but I think it would be worth your time to get the right power supply and use the pedal as it's supposed to be. I can't see that modding a whammy to use DC would do you any better because of the high mA needed still - the one spot would be nearly used up with just the whammy! That's my 2cents but what do I know!

A friend of mine had a Wh-4 with a dead ps that he gave me.

Also, getting a free WH4 is freaking awesome! I wish I had friends as great as yours! I wouldn't complain too much about a $40 powersupply if it made the pedal work. It sounds to me like you've spent enough time and energy trying other alternatives that it may have been worth it just to spring.

Perhaps the OP could do that? Have you looked into the cost and such?

Jacob

[ppatchmods]

i actually don't use wall warts on my board. i have 2 battery powered supplies that run off of 6 "c" batteries each. one i use to power my delay and modulation pedals and the other for dirt. the batteries will last about 24 solid hours in the dirt supply and about 15 in the other. i don't really like to have a bunch or extension cords lying around. i was think i could build a supply just for the whammy.

[jkokura]

I wonder if you can get 9V AC from C batteries. I assume your batteries are rechargeable? I think that could be a cool project.

Otherwise, we're back to either modding to accept DC or buying a powersupply. Have you tried the suggestion to see if DC will work with it now?

Jacob

[space_ryerson]

Also, getting a free WH4 is freaking awesome! I wish I had friends as great as yours! I wouldn't complain too much about a $40 powersupply if it made the pedal work. It sounds to me like you've spent enough time and energy trying other alternatives that it may have been worth it just to spring.

Perhaps the OP could do that? Have you looked into the cost and such?

Jacob

Oh, indeed it was awesome! I was just hanging out with my friend, and he says, "Oh, you like to modify and build pedals, I have something for you." He walked away, and I had no idea what he would come back with, but I definitely wasn't thinking a WH-4!

If I didn't already own a WH-2, I would have already bought the adaptor. Looking back at my notes, the Digitech's part number for the WH-4 adaptor is PS0913B-120.

[Processaurus]

Your whammy pedal takes a ton of current, I have the version before and it takes 750mA.  Your ingenious battery pack just won't last, even if you could heroically hack the whammy to accept DC.

Just plug the DC adapter in and see what happens. There usually isn't any harm in doing so, the only loss is a diode drop or two and ground not actually being at 0VDC because of any types of rectifiers. (NOTE: You can't do the opposite, Eg. plugging AC adapters into units without rectifiers!)

It would probably sound all distorted.  If it is like the XP version it has a bipolar supply (like most AC powered pedals), and a separate plus supply for the digital circuitry.  You could feed the correct polarity DC to the + rectifier, and make a -5 supply for the analog section's opamps with a robust charge pump running off the analog +5, however the DC PSU would need to be beefy, to run the CPU.  Also it would probably kick plenty of digital noise back on the rails, which could cause problems if other effects shared the supply.

A friend of mine had a Wh-4 with a dead ps that he gave me. I tried using my WH-2's ps (9v AC, 900mA I think), and the WH-4 just does this 'one led flash no work' thing. So, I tried a non-digitech 9v AC 1.3 amp ps, and have the same problem! I tested the voltage from the ps, and it was closer to 10v AC, so I called Digitech, and they sell the bloody ps for $40! I'm all ears for a solution that doesn't involve me paying $40 a ps that will just fail in a year or two.

It is doubtful the power supply is the problem, their $40 9v AC is the same thing as both of your other power supplies.  You might check the outputs of the regulators in the power supply instead, they are probably 7805 and 7905, and should put +5 and -5 out of their outputs respectively. Pin 3 is out on the 7805, Pin 1 is out on 7905.

http://www.national.com/ds/LM/LM340.pdf

What would be cool is do what digitech could have done, if UL wasn't so expensive, and put a toroidal 9v AC transformer inside, and run it off 110, like olden pedals.

[space_ryerson]

Thanks Ben. If I have time when I get home tonight, I'll check it out.

[G. Hoffman]

Voodoo Labs does make an AC Pedal Power, which they say is designed for (among other things) the Whammy pedals. 

Also, Webber's pedal PS transformer has a 9V 2A output.


Doesn't help you with the batteries, but still.


Gabriel

[space_ryerson]

A friend of mine had a Wh-4 with a dead ps that he gave me. I tried using my WH-2's ps (9v AC, 900mA I think), and the WH-4 just does this 'one led flash no work' thing. So, I tried a non-digitech 9v AC 1.3 amp ps, and have the same problem! I tested the voltage from the ps, and it was closer to 10v AC, so I called Digitech, and they sell the bloody ps for $40! I'm all ears for a solution that doesn't involve me paying $40 a ps that will just fail in a year or two.

It is doubtful the power supply is the problem, their $40 9v AC is the same thing as both of your other power supplies.  You might check the outputs of the regulators in the power supply instead, they are probably 7805 and 7905, and should put +5 and -5 out of their outputs respectively. Pin 3 is out on the 7805, Pin 1 is out on 7905.

http://www.national.com/ds/LM/LM340.pdf

What would be cool is do what digitech could have done, if UL wasn't so expensive, and put a toroidal 9v AC transformer inside, and run it off 110, like olden pedals.

I probed what I think are the regulators. On the board they are labeled 'U1', 'U2', and 'U3'. U1 and U2 have difficult to remove heatsinks surrounding them, so I can't read what parts they are. U3 is a 7905A. The input of the 7905A is input voltage is -14v, and the output voltage is -4.9v. U1's pins read 4.47v, 1.30V, and -.010v. U2's pins read .186V, -.02v, and 12.96v.

U1 and U2 get pretty hot, which has me concerned. If I could get the heatsinks off of the them, I could at least read the datasheets for what they are, and decide if those voltages are quirky.

[jakehop]

AFAIR the two remaining regulators are 7812 and 7912 providing 12V each. The reason they get hot is that the effect draws a LOT of current. It would be insane to have this pedal running on batteries, unless you have a steady supply of laptop-batteries.

However, small, ceramic caps across the regulators can greatly help decrease digital PS-noise which some of the WH-4s have.

Jake

[DougH]

IMO, I wouldn't mess with it. Get a power supply for your pedalboard, like the Voodoo Labs thing.

DSP units like Whammy pedals are basically computers in a small box. They have higher current draw and more specialized filtering requirements than typical analog 9v pedals. You are way out of the 9v and/or battery paradigm when you step into the world of DSP. If you want to lose the wall-wart they supplied you will have to step up to a pedalboard power supply of some sort. There's no free lunch here.

[zyxwyvu]

Also, Webber's pedal PS transformer has a 9V 2A output.

IMO, I wouldn't mess with it. Get a power supply for your pedalboard, like the Voodoo Labs thing.

I power my Whammy 4 with my DIY spyder style power supply. It uses the Weber power transformer's 9V AC output. The only difference I've noticed is it takes a fraction of a second longer to start up than with the power supply that came with the pedal.

[DougH]

Yes, you can always build your own power supply like a Spyder.

But I wouldn't advise a battery powered scheme or hacking into the DC power bus of the pedal and using the typical 9VDC (from a wall-wart or otherwise).